1. Field of the Invention
The present invention relates to separation and analysis of hop bittering components (bittering components originated from hops). More particularly, the present invention relates to an analysis method and an analysis equipment for separating and analysing bittering components contained in rough hops, hop products or hop drinks such as beer, by simple operation and with high precision.
2. Description of the Prior Art
Bitterness of hop drinks such as beer, results from bittering components originated from hops, and the bittering components are understood to be consisting of humulones (.alpha.-acids), such as humulone, cohumulone, adhumulone, etc., and isohumulones (iso-.alpha.-acids), such as isohumulone, isocohumulone, isoadhumulone, etc. Analysis of these bitter components is of great significance for the control of beer manufacturing process, especially beer brewing process, and the control of quality of the final beer. Analysis of the above-mentioned components is important also in respect of the control of bitterness of other hop drinks, the control of different bittering components due to the difference in the growing district and the harvesting season of the rough hops and accordingly the control of purchase and receiving of the rough hops.
Hitherto, analysis of such bittering components, especially of the bittering components in hop drinks such as beer, has been performed according to a process wherein a sample to be tested is subjected to extraction treatment with isooctane or methanol under acidic condition by hydrochloric acid, the organic phase is evaporated to dryness and then diluted with methanol to a prescribed volume, and the resulting solution is subjected to ion-exchange chromatography or reversed phase chromatography to separate, analyse and estimate the bittering components [M. Verzele, C. Dewaele: ASBC. J. 39, No. 2, 1980 and J. Chromatogr., 197. 189. 1980]. Without such extraction treatment, separation of bittering components was hindered by coloring matters, protein, etc. coexisting in the sample, and it was difficult to estimate the bittering components by liquid chromatography.
However, the conventional method as mentioned above involves problems that (1) operations for the extraction are troublesome, (2) about 1 hour is requested for the preparation of one sample, (3) the large amount of extracting solvent consumed results in the high cost of analysis, (4) errors in the operations for extraction are gross, and so forth.
In view of such problems, the present invention has been made to provide an analysis method and an analysis equipment for separating and analysing bittering components in hops, hop products and hop drinks containing other coexisting components, by rapid and simple operation and with high precision, without effecting any operation for the extraction.